AT&T says it has activated more than 1 million Apple iPhone 4S's

The nation's second largest carrier announced the massive number on Thursday and said that the iPhone 4S has been its "most successful iPhone launch in the company's history."

To put that in a bit of context, Apple said on Monday that the iPhone 4S sold more than 4 million units worldwide over its Friday-Saturday-Sunday launch last weekend.

That set a sales record for iPhones over a three-day launch period.

AT&T has been selling the iPhone since the launch of the first-generation Apple smart phone in 2007.

On Thursday, in mentioning that it has sold 1 million iPhone 4S handsets, AT&T also took the opportunity to mention that its iPhone 4S, while still considered a 3G phone, is capable of reaching 4G-like speeds because it runs on an HSDPA network. Sprint and Verizon's iPhones run on CDMA networks which, while still fast, don't offer the same potential high speeds.

The AT&T iPhone 4S is also the only iPhone 4S that allows users to talk and use Web data at the same time.

While AT&T is the first U.S. carrier to offer up any specific numbers, Sprint has said that on launch day alone, the iPhone 4 and 4S had already resulted in its "best-ever day of sales in retail, web and telesales for a device family in Sprint history."

[Updated 12:26 p.m.: An earlier version of this post incorrectly stated that the Sprint and Verizon iPhones ran on GSM networks. Sprint and Verizon's iPhones run on CDMA networks.]